Chris@126: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@126: 
Chris@126: /*
Chris@126:     QM DSP library
Chris@126:     Centre for Digital Music, Queen Mary, University of London.
Chris@126:  
Chris@126:     This program is free software; you can redistribute it and/or
Chris@126:     modify it under the terms of the GNU General Public License as
Chris@126:     published by the Free Software Foundation; either version 2 of the
Chris@126:     License, or (at your option) any later version.  See the file
Chris@126:     COPYING included with this distribution for more information.
Chris@126: */
Chris@126: 
Chris@126: #include "SincWindow.h"
Chris@126: 
Chris@126: #include <cmath>
Chris@126: 
Chris@126: void
Chris@126: SincWindow::init()
Chris@126: {
Chris@126:     if (m_length < 1) {
Chris@126: 	return;
Chris@126:     } else if (m_length < 2) {
Chris@126: 	m_window.push_back(1);
Chris@126: 	return;
Chris@126:     } else {
Chris@126: 
Chris@126: 	int n0 = (m_length % 2 == 0 ? m_length/2 : (m_length - 1)/2);
Chris@126: 	int n1 = (m_length % 2 == 0 ? m_length/2 : (m_length + 1)/2);
Chris@126: 	double m = 2 * M_PI / m_p;
Chris@126: 
Chris@126: 	for (int i = 0; i < n0; ++i) {
Chris@126: 	    double x = ((m_length / 2) - i) * m;
Chris@126: 	    m_window.push_back(sin(x) / x);
Chris@126: 	}
Chris@126: 
Chris@126: 	m_window.push_back(1.0);
Chris@126: 
Chris@126: 	for (int i = 1; i < n1; ++i) {
Chris@126: 	    double x = i * m;
Chris@126: 	    m_window.push_back(sin(x) / x);
Chris@126: 	}
Chris@126:     }
Chris@126: }
Chris@126: